EVP voltage above closed limit?

[Papageof]

-EVP voltage above closed limit-


Does this mean the egr valve is not closing or what? That would explain my slightly rough idle. Also, i got a secondary fuel circuit code, what is that about?

 

[Michael Yount]

At idle with the engine warm, pull the vacuum hose off the egr valve. Nothing at all should happen because at idle there should be no vacuum present at that hose. If you pull it off (hold your thumb over the hose), and the idle smooths out, then it's likely either a problem with the egr vacuum switch (firewall), the wiring harness has an issue, or the ecu is sending an errant signal (unlikely).

 

[Papageof]

Well, i did disconnect the vacuum line and and there was no vacuum present so i don't think the switch is bad. After thinking about it, I think it is most likley the valve is crusted up and stuck open a hair. I wasn't able to check it as my "play time" was almost up and I didn't have a gasket for it on hand (shame on me!) . I am gonna pull it off tommorow if i get time.
Thankyou for your response.
Now to figure out the fuel ckt problem. If the fuel pump works, what could be wrong?

 

[Michael Yount]

I think you're right - switch sounds ok; maybe sticking open. Not sure about fuel pump - I'm used to a different arrangement there than you.

 

[jrichker]

Post the actual codes - I have a list of what you need to do to fix many of the common codes for 86-93 Mustangs

 

[Papageof]

If i remember they were, Continuous:
34-EVP voltage above closed limit (SONIC)
and either:
95 -Fuel pump secondary circuit failure
or:
96 -Fuel pump secondary circuit failure
asside from my smog pump stuff. These listings are from the corral but match my haynes.

 

[2muchtime]

your egr pintle position is not fully closing which will set that code.
(sticking in open position) will cause a slightly rough idle.

 

[Papageof]

Yeah, that is what i was thinking i am just waiting for it to cool off outside before i go check it. THe funny thing is i don't remember ever seeing the check engine light come on.

 

[Papageof]

Doh! Ignore this post.

 

[Papageof]

EGR valve checked and cleaned no better on the idle, it almost sounds like a tiny miss when I rev very slowly... Time for plugs, wires, cap rotor, etc again i guess.

Anyone have an Idea about that fuel pump ckt thing?

 

[jrichker]

Code 34 EGR voltage above closed limit - Failed sensor, bad or missing signal ground, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the EGR valve by mouth. If you can, replace the EGR valve ($85-$95).

If the blow by test passes, and you have replaced the sensor, then you have electrical ground problems. Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the black/white wire and the negative battery post. It should be less than 1 ohm.

 

[Papageof]

I cleaned it and all seemed well with the valve itself I haven't done anything with the sensor. I am really concerned with the fuel ckt thing. That could leave me stranded ya know?

What is the secondary fuel pump ckt?

 

[jrichker]

Code 95 - Possible bad fuel pump ground or open between fuel pump and pin 8 at PCM (Fuel Pump Monitor signal) - Power / Fuel Pump Circuits

For 87-90 model cars, to help troubleshoot the 95 code, follow this link for a wiring diagram http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

For 91-93 model cars, help troubleshoot the 95 code, follow this link for a wiring diagram http://www.autozone.com/images/cds/gif/large/0900823d80195963.gif

Also see http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp

Check the black wire that comes out of the tank; it is the fuel pump ground. It goes to a 2 wire connector and then ground to the chassis. If the connections get dirty or corroded, you will lose fuel pressure.

Code 96 – KOEO- Fuel pump monitor circuit shows no power - Fuel pump relay or battery power feed was open - Power / Fuel Pump Circuits.

Look for a failing fuel pump relay, bad connections or broken wiring. The fuel pump relay is located under the Mass Air Meter on Fox bodied stangs built after 91. On earlier model cars is under the passenger seat.

To help troubleshoot the 96 code , follow this link for a wiring diagram for 91-93 models see http://www.autozone.com/images/cds/gif/large/0900823d80195960.gif

Look for power at the fuel pump - the fuel pump has a connector at the rear of the car with a pink/black wire and a black wire that goes to the fuel pump. The pink/black wire should be hot when the test connector is jumpered to the test position. . To trick the fuel pump into running, find the ECC test connector and jump the connector in the lower RH corner to ground. http://www.mustangworks.com/articles/electronics/eec-iv_codes.html for a description of the test connector. it. No voltage when jumpered, check the fuel pump relay and fuse links.

 

[Papageof]

G, Goshous, Golly that all sounds like fun! The thing i don't get is the car runs more or less fine. If the fuel pump ckt was bad wouldn't it stop the pump?

 

[jrichker]

Codes 95 & 96 - the pump circuit lost power at some time in the past. If you had a time when the car wouldn't start or suddenly spit or sputtered, that was when it happened.

 

[Papageof]

That makes sense I just don't remember it happening. The only time the car didn't start was when the battery went out over a year ago. Otherwise, the car is preatty reliable. These codes couldn't be more than two weeks old cause that is when i installed my 3g, the battery was disconnected most of the day.